EVANSTON – With Ohio State looming on the schedule, Northwestern coach Pat Fitzgerald had hoped Saturday's game against Maine would serve as sort of a tune-up for his high-powered offense to start running smoothly.

Instead, the offensive inconsistencies lingered and only a pair of defensive scores — interception returns for touchdowns by linebacker Damien Proby and Sean Lowry —prevented a possible upset in as the 18th-ranked Wildcats held on for a 35-21 victory.

"When we're in position, we have to make plays," Fitzgerald said. "It's similar to last week when we couldn't get out of our own way."

Following two impressive victories over California and Syracuse, Northwestern (4-0) has had a couple of ho-hum performances against Western Michigan and Maine.

"It's obviously great to win the ballgame, but we know that we have so much more left in the tank," wide receiver Tony Jones said. "At the same time, it's pretty exciting to know we're winning ballgames. This is the second straight week we came back knowing we could have played a lot better.

"It just keeps us hungry. We know the potential this team has if we actually play up to our capabilities."

Led by quarterback Marcus Wasilewski, Maine (3-1) actually outgained Northwestern in total offense (379 to 373). The Black Bears also were left thinking what might have been if they executed a couple of plays better.

"I thought maybe if we don't throw two interceptions they run back for touchdowns, we're still playing," Maine coach Jack Cosgrove said. "I think we played real hard. I liked the way we finished the football game offensively, because we had some rough goes — we didn't finish some drives in the first half of the football game."

Northwestern scored on its first offensive possession as quarterback Kain Colter (5-for-9 for 85 yards with a touchdown and an interception) and Jones hooked up on a 27-yard scoring pass to cap a nine-play, 76-yard drive with 10:18 left in the opening quarter. That was the Wildcats last offensive score until the fourth quarter. Fortunately for Northwestern, the defense came through.

Proby had a 49-yard interception return for a touchdown in the final minute of the second quarter to give Northwestern a 14-0 lead. On the play, Wasilewski's pass was tipped by receiver Derrick Johnson and Proby snatched it out of the air and headed the other way with a convoy of blockers along for the ride.

Proby said that was the first pick six of his life.

"That was an exciting one," he said. "I'm happy for it."

Less than five minutes into the second half, the defense made another huge play. Proby pressured Wasilewski and caused the quarterback to lose control of the pass as he attempted to throw on the run. Lowry scooped the floating pass and returned it 19 yards for the score to make it 21-0.

"I definitely feel more confident out there after playing 13 games as a backup (last season)," said Lowry, a sophomore. "The game's a little slower out there than it was last year and I'm going out there knowing the game plan a little bit better and what the guys around me are doing."

Maine finally got on the board with 3:02 left in the third as Wasilewski found tight end Justin Perillo for an 11-yard scoring pass to make it 21-7.

Northwestern, though, dashed hopes of a Maine comeback on the ensuing possession when the offense produced an 8-play, 74-yard scoring drive capped by running back Mike Trumpy's 7-yard run that made it 28-7 five seconds into the fourth quarter.

Maine managed a couple more touchdowns down the stretch wrapped around a 5-yard scoring run by Colter to make the score tighter. But the Black Bears never were a serious threat to win the game.

NU has a bye next week, so it has extra time to work out the kinks and prepare for No. 4 Ohio State at home on Oct. 7.

"I think we've been a part of a lot of games that are important," Fitzgerald said. "This is the first opportunity to play Big Ten football, so that's why it's important. That's why all of our guys come here. It's one of the first things we talk about in recruiting, is the opportunity to play Big Ten football at the best academic school in the country.

"And our guys are excited for that challenge to play in this conference. We got through the nonconference slate unblemished and that's kind of the goal and now everything starts over."